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-   -   Yanmar Transmission Clutch Problem (http://www.sailnet.com/forums/diesel/92041-yanmar-transmission-clutch-problem.html)

ncapener 09-12-2012 07:56 PM

Yanmar Transmission Clutch Problem
 
Hello,

I have a 3 HM 35 engine with a KBW10 transmission.
Recently the clutch started to slip, now it does not engage at all.
I took the transmission out and the cover off. I am looking inside the housing at two shafts with gears on them, a shift fork and what appears to be clutch plates on the larger shaft.
I would like to repair/ replace the gear box myself. How do I proceed ? Drawings or pictures available anywhere? I think, I can get the parts. I am not a mechanic, but I have a good set of tools and have taken a VW transmission apart once and changed the synchro rings....
Anybody done that job and can help?

If not possible to repair, Is there a way to lock the gear box in forward to get home???

Thanks,
Neal

Capt. Gary Randall 09-12-2012 10:36 PM

Re: Yanmar Transmission Clutch Problem
 
hello there, First of all ,Do you know exactly what caused the problem in the first place. Did it run out of oil? Do you see Water in the transmission? Do you think it has that many hours on it that is actually just naturally wore the clutches?? Do you have a bearing failure? Is there any metal in the case? Are the metal filings magnetic? captg

kd3pc 09-13-2012 07:40 AM

Re: Yanmar Transmission Clutch Problem
 
some manuals and parts breakdown are available on the net...I found the kbw 20

the real chore is getting the parts, even the wear items are tough. Since you have it out, you will need to source clutch plates and bearings, but it would be good to know what caused the clutch to start to slip....lack of use and the wrong lube are the biggest causes ....

BTW, it is not a VW and unless your tool box is quite full, you will need some special tools to repair without damage. The clutch pack is more like a motorcycle one, multiple plates and wear discs stacked in a spring loaded can. You need to be able to measure .0079 wear, as well as gear tooth contact of 70%. thrust washers have to be facing the correct way. Heating the cases to remove bearing races is an art in itself. These are the biggies that I recall in rebuilds I did a few years back.

The there is the adjustments.

exchange is fairly pricey, and unless you know the builder and what he replaced, you may end up worse off

best of luck

ncapener 09-13-2012 03:58 PM

Re: Yanmar Transmission Clutch Problem
 
Did not run out of oil, no water in tranny. Engine is from the mid 80's no hour meter. Fluid dark, some metal shavings, brass in color. Don't know if the bearings are bad (yet).

Quote:

Originally Posted by Capt. Gary Randall (Post 921588)
hello there, First of all ,Do you know exactly what caused the problem in the first place. Did it run out of oil? Do you see Water in the transmission? Do you think it has that many hours on it that is actually just naturally wore the clutches?? Do you have a bearing failure? Is there any metal in the case? Are the metal filings magnetic? captg


ncapener 09-13-2012 04:15 PM

Re: Yanmar Transmission Clutch Problem
 
It seems the thrust washer and clutch plates are available.
I am sure I use the correct fluid and it's not the lack of use that caused the failure.
From the first time I noticed a slip to no engagement whatsoever app. 50 hrs.

I found some crusty old Viking mechanic who claimes an idle too low caused that failure. The Yanmar dealer thinks having the gear box in forward while sailing is too blame.

Can you tell me how the clutch pack is removed from the shaft and how to disassemble it?
I am looking at the shaft and don't know how to proceed. I would be happy if I can temporarily "fix" the thing without new bearings. If I can get two more days of motoring out of it I can get home. Otherwise I have to wait for the next S gale and this time of the year that could take a while:)

Quote:

Originally Posted by kd3pc (Post 921690)
some manuals and parts breakdown are available on the net...I found the kbw 20

the real chore is getting the parts, even the wear items are tough. Since you have it out, you will need to source clutch plates and bearings, but it would be good to know what caused the clutch to start to slip....lack of use and the wrong lube are the biggest causes ....

BTW, it is not a VW and unless your tool box is quite full, you will need some special tools to repair without damage. The clutch pack is more like a motorcycle one, multiple plates and wear discs stacked in a spring loaded can. You need to be able to measure .0079 wear, as well as gear tooth contact of 70%. thrust washers have to be facing the correct way. Heating the cases to remove bearing races is an art in itself. These are the biggies that I recall in rebuilds I did a few years back.

The there is the adjustments.

exchange is fairly pricey, and unless you know the builder and what he replaced, you may end up worse off

best of luck


Brent Swain 11-13-2012 09:58 PM

Re: Yanmar Transmission Clutch Problem
 
When trannys start to get slow to kick into gear , its time to change the oil. The oil will look super clean on the dipstick, but drain it and it looks like mud in the can. Takes longer and longer for the plates to connect thru the crud. Some times one oil change, run it a bit, then another oil change, is needed.

Omatako 11-25-2012 07:36 PM

Re: Yanmar Transmission Clutch Problem
 
You could start here:

Clymer Yanmar Diesel Inboard Shop Manual One, Two and Three Cylinder Engines 1980-2009

Having a workshop manual is like lifting the veil.

Good luck

ncapener 11-27-2012 12:31 PM

Re: Yanmar Transmission Clutch Problem
 
I got the shop repair manual in PDF from the dealer for my engine. The transmission was included.

The old Viking mechanic repaired the tranny. Replaced the 16 clutch plates and one bearing for $600. Buying the clutch plates alone from the dealer without shipping and taxes would have exceeded that amount. One clutch plate is $85!!!

WCS, worst case scenario, a new tranny is $1600.

Neal

Maine Sail 11-27-2012 01:08 PM

Re: Yanmar Transmission Clutch Problem
 
Quote:

Originally Posted by ncapener (Post 953788)
I got the shop repair manual in PDF from the dealer for my engine. The transmission was included.

The old Viking mechanic repaired the tranny. Replaced the 16 clutch plates and one bearing for $600. Buying the clutch plates alone from the dealer without shipping and taxes would have exceeded that amount. One clutch plate is $85!!!

WCS, worst case scenario, a new tranny is $1600.

Neal

Neal,

I am fairly certain that model gear is actually a Hurth/ZF box rebadged as a Kanzaki (KBW vs HBW). What usually goes in them is the thrust washer but s the fluid gets dirty it can take out the plates too. This can happen due to leaving the gear in forward when sailing and then not changing the fluid asap.

They are splash lubed and the metallic bits wind up a the bronze thrust washer and eat it..

These boxes NEED the transmission fluid changed every year, at a bare minimum..

ncapener 12-14-2012 09:54 PM

Re: Yanmar Transmission Clutch Problem
 
Now that I know how the clutch works I can see why clean fluid is so important.
From now on I might as well change the fluid every time I change the engine oil.

I don't think that leaving the tranny in gear while sailing is a bad thing. Actually, I think it is better in gear than not. When in gear, nothing is moving. In neutral the prop turns the shaft which turns the clutch plates rubbing against the pressure plates.
The manual does not mention anything about sailing in gear or not.


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